Two people are under arrest, including a mother who police say had a baby at home. That child's body turned up in a Fresno canal. Now investigators have to find out if it's a murder case.

An autopsy wrapped up late Thursday afternoon. But much of the evidence police need to determine a cause of death is gone. So police are now hoping to find neighbors or witnesses to tell them how this newborn's life ended.

Fresno police say 26-year-old Stefanie Saylor had a baby several months ago. But what happened after she gave birth at home, remains unclear. She claims the baby was stillborn, according to detectives.

Fresno Police Chief Jerry Dyer said, "We don't know if the child was born stillborn, died of natural causes after the birth or was murdered."

Investigators have the difficult task of trying to figure out what happened at the Cambridge Court Apartments, where Saylor and Joseph Castro lived. They want to talk to neighbors who may have seen the baby and more about the circumstances surrounding the delivery.

The police chief says Saylor has three other children, and in February took them to an amusement park, but what she left at home in her apartment was shocking and disturbing.

"At some point and time, Stefanie ends up, after giving birth, ends up going to Disneyland. And we know that to be in late February and subsequent to that, at some point and time, that her live in boyfriend, Joseph Castro finds that baby in the closet, underneath some blankets."

Police say Jeryl Garrard helped Castro get rid of the dead baby by putting it in a plastic tub, then putting trash over it and placing it at the curb. But when it wasn't picked up, police say the men then caste the infant in cement and put it in a plastic bag. Eventually the baby was placed in a canal behind the apartment complex.

Saylor declined to talk to ABC30 before she arrested by police. Investigators say several medical tests were taken during the autopsy to try and determine the child's age and sex.

Right now, it's unclear what criminal charges, if any these suspects could face. Castro is being held on a parole violation and Saylor is under arrest for a probation violation.